Urea-group containing polyisocyanate mixtures which are liquid at room temperature are known. See U.S. Pat. Nos. 4,611,083 and 4,703,100. Such mixtures are described as being prepared by reacting polyoxyalkylene polyamins having functionalities of from 2 to 5 and amine numbers of from 20 to 250 with specific polyisocyanates based on diphenylmethane diisocyanate. The polyisocyanates used are selected from the group consisting of (i) at least one diphenylmethane diisocyanate isomer and (ii) a mixture of diphenylmethane diisocyanates and polyphenyl polyethylene polyisocyanates where the diisocyanate content of the mixture is from 55 to 90 weight percent. See also U.S. Pat. No. 4,689,356. Similar products are described in U.S. Pat. No. 4,705,814, but the isocyanate used is an aliphatic isocyanate.
It is also known that diphenylmethane diisocyanate and its higher derivatives can form stable prepolymers with primary amine terminated materials having a degree of amination of from about 25 to 85% and with secondary amine-terminated materials having a degree of amination of from 25 to 100%. See, U.S. Pat. No. 4,686,242. The amines described in this reference are prepared by reacting a hydroxyl-terminated polyether with hydrogen and ammonia or a primary amine in the presence of catalysts to reductively aminate the polyether.
Isocyanate prepolymers are also known which can be prepared by reacting aromatic isocyanates with aromatic amine-amides. See, U.S. Pat. No. 4,609,683. The amides are described as being prepared by reacting isatoic anhydride with a polyoxyalkylene polyamine. Similar amides are described in U.S. Pat. Nos. 4,180,644 and 4,609,684, for use in making a variety of polyurethane type materials.
Compounds having terminal aromatic amine groups and having the general structure: ##STR3## are known. In U.S. Pat. No. 3,808,250, X is defined as oxygen or sulfur, n is an integer of from 2 to 8, and R is defined as an n-valent radical obtained by the removal of hydroxy groups or mercapto groups from an n-valent polyether or polythioether having a molecular weight of from 600 to 10,000. U.S. Pat. Nos. 3,817,940 and 3,929,863 describe similar compounds where R is based on a polyol or polythiol having a molecular weight of less than 600. U.S. Pat. Nos. 3,975,428 and 4,016,143 describe similar compounds prepared by reacting isatoic acid anhydride with a compound containing at least two hydroxyl groups and at least one tertiary nitrogen group and having a molecular weight of from about 119 to about 1000. Similar compounds are described in U.S. Pat. Nos. 4,136,091, 4,169,206, 4,186,257, 4,228,249 and 4,260,557. Para substituted compounds are described in U.S. Pat. Nos. 4,504,648 and 4,515,981. Finally, similar para-, meta- and di-meta substituted compounds are described in U.S. Pat. Nos. 4,328,322 and 4,732,959. While all of these references describe that the compounds disclosed can be used to manufacture polyurethane products, none describe liquid isocyanate-terminated prepolymers.
Recently have been disclosed poly(amino aromatic) compounds of the structure ##STR4## where R is an n-valent group obtained by the removal of the hydroxyl or mercapto groups from an n-valent polyol or polythio having a molecular weight of from 400 to about 12,000, A is hydrogen or an inert substituent, X represents oxygen or sulfur, n represents an integer of from 2 to 8, and y is 1 or 2. See European Patent Application No. 0,268,849 and U.S. application Ser. No. 183,556, filed Apr. 19, 1988. Such compounds are described as useful in preparing polyurethane elastomers.